A tread kerf (or sipe or fine groove) of a snow tire, formed in the outer surface of a tread block of the snow tire in a depth direction of the block in a shape of a trapezoidal wave (100), extending along the outer surface of the block, wherein the distance L1 of the upper portion (110) of the trapezoidal wave, as viewed in a top view of the block, is less than the distance L2 of the lower portion (112) of the polygonal wave such that side surfaces (113) linking the upper (110) and lower (112) portions of the wave are formed as inclined surfaces (113), the distance between which decreases toward the upper portion (110).
